Taking Poria coccus as material,the extraction technology of polysaccharides from it was optimized by response surface methodology and its immune activity was studied.The results showed that the optimum extraction conditions of polysaccharides from Poria coccus was microwave power 471.3 W,microwave extraction time 8.5 min,ethanol concentration 82.3%,solution and material ratio 19.9,under these conditions,the polysaccharides yield could reach 2.96%.The polysaccharides from Poria coccus had proliferative effect on leukomonocyte.The proliferative effect strengthened gradually with the concentration of polysaccharides from Poria coccus increased.When its concentration exceeded 100 μg/mL,the proliferative effect decreased.